Flame resistant fabrics are used in numerous applications. In many environments, for instance, garments and apparel with flame resistant properties are highly desirable in order to protect the wearer. For example, military personnel operating in war zones can be exposed to various incendiary devices. Wearing fire resistant garments in such environments can minimize harm to the wearer and ultimately can prevent the loss of life.
In fact, the United States Military Services are currently providing those in combat zones with flame resistant garments to protect against burn injuries. Such garments should have excellent flame resistant properties. For instance, the garments should perform well when tested according to ASTM Test F1930, which is referred to as the Thermal Mannequin Test. During the Thermal Mannequin Test, the garment is placed on a mannequin and exposed to a massive flame event. Specialized sensors are placed on the mannequin to monitor and predict burn injury. ASTM F1930 testing conducted using exposure to a simulated 4 second flash fire predicts that FR garments currently used by the US Army will help protect the wearer from suffering second and third degree burn injuries underneath these FR garments. The current FR Army Combat Uniform, for example, is predicted by ASTM F 1930 to limit the amount of body area suffering from second and third degree burns under the uniform to less than 35% when exposed to a simulated 4 second flash fire.
Electrical workers, firefighters, police personnel, oil rig workers and many other occupations face similar burn threats on a regular basis while operating outside, often in inclement conditions while carrying heavy loads. Unfortunately, because of the limitations of existing flame resistant fabrics, these workers, like the military personnel, must often compromise weight, durability and environmental protection when they don traditional flame resistant clothing.
In the past, many fire resistant garments and other clothing articles were made from fabrics containing primarily or exclusively aramid fibers. Aramid fibers, such as para-aramid fibers and meta-aramid fibers, for instance, have inherent flame resistant properties. Producing a fabric exclusively from aramid fibers, however, can have various disadvantages. For instance, such fabrics are not only relatively expensive to produce, but aramid fibers have historically not always been readily available. In addition, these fabrics are difficult to dye and are not amenable to many printing processes. Furthermore, due to the limitations in aramid fiber size availability and the inability to make a complete array of yarn sizes, the fabrics may not have a desired combination of properties such as strength, weight, breathability, drape, hand, durability and the like.
In order to improve one or more properties of fabrics containing aramid fibers, those skilled in the art have proposed blending the aramid fibers with other flame resistant fibers, such as FR cotton.
One problem that has continued in the design and construction of flame resistant fabrics is the inability to produce fabrics containing substantial amounts of synthetic fibers, particularly polyester fibers, polyolefin fibers, and/or nylon fibers, that possess desirable flame resistant properties. The above synthetic fibers, typically found in the highest performing non-flame resistant apparel designed for rugged outdoor use, are desirable because they enable the construction of superior performing fabrics with respect to weight, durability, hand, drape and environmental protection. Unfortunately, the above synthetic fibers have a tendency to burn, drip and melt when exposed to an open flame. Thus, polyester fibers and nylon fibers have been used in relatively minor amounts in flame resistant fabrics, such as by being present in amounts no more than about 20% by weight. Thus, a need exists for a fabric construction and a fabric treatment that are capable of producing a fabric product containing substantial amounts of non-inherently flame resistant synthetic fibers, while still possessing the desired flame resistant properties and protection from burn injuries. There is also a need for systems and methods for producing the fabric products.